(1) Field of the Invention
The present invention relates generally to electric energy generation from mechanical sources and, more particularly, to a transducer module that is optimized to generate electrical energy from environmental, mechanical, and mechanical compression forces that otherwise could not be used.
(2) Description of the Prior Art
While piezoelectric materials have been successfully utilized in sensors and actuators, their use as practical power sources for generating a useful amount of electricity in portable generators has been limited. Users of piezoelectric devices are presently substantially limited to operating only very low power devices, such as LEDs. This operation is typically limited to only a brief flash.
For practical use, the inventor believes that to power portable electrical devices, it would be necessary that electricity be generated using a large number of piezoelectric transducers. Preferably, such a system would be able to store power generated over a period of time. Thus, a practical system would require signal conditioners such as rectifiers and power storage, such as batteries. The need for a large number of piezoelectric transducers with many interconnections between components such as rectifiers and batteries increases the weight, reduces the robustness, and increases the complexity and difficulty of packaging such devices, especially for purposes such as being carried on a person, device, or object. Moreover, a practical system should be adaptable for capturing energy produced by different types of motions, with different amounts of force or translational movement. The prior art does not address the above problems.
The following U.S. patents describe various prior art systems that may be related to the above and/or other transducer module systems.
U.S. Pat. No. 5,955,790, issued Sep. 21, 1999, to North, discloses a power transfer system for generating electrical energy from recurring wave and tidal movement within the ocean. The system comprises a pressure sensing device, such as an array of pressure transducers, positioned at the ocean floor below water level and at a location of wave movement for (i) registering changes in height of water above the pressure sensing device and (ii) providing a power output corresponding to changes in force associated with the changes in the height of water. A transfer medium is coupled at one end to the pressure sensing device and extends underground to a second end at a shore location adjacent the location of wave movement for transmitting the power output of the pressure sensing device to the shore location. A bank of storage batteries is coupled to the transfer medium at the shore location for receiving the power output from the transfer medium and for storing the power output as a useful form of energy.
U.S. Pat. No. 6,438,242, issued Aug. 20, 2002, to Howarth, discloses an electro-acoustic transducer in which a plurality of cymbal-type electro-acoustic actuators are disposed in mechanical and electrical parallel between a pair of stiff plates. The resultant transducer resonates at a lower frequency than the cymbals, with a greater generated force. An example of a plurality of cymbal type transducers is shown in FIG. 1.
U.S. Pat. No. 6,737,789, issued May 18, 2004, to Radziemski, et al., discloses a force activated electrical power generator using piezoelectric elements of preferred lead-magnesium-niobate lead titanate (PMN-PT). The circuitry is in preferred versions completely passive generating all power needed. Some circuitry limits voltage across the elements and provides a return charge channel to prevent depolarization. Transformers can be used to increase the output voltage and efficiency. Rectifiers are shown to rectify the output to a single polarity. Filtering, regulation and other conditioning components are also shown. The output from the generator and circuitry can store the electrical charge, such as in a capacitor and/or battery.
U.S. Pat. No. 7,157,802, issued Jan. 2, 2007, to Bodkin, discloses an electrical power source that derives input power from a compressed gas which is fed into a transducer, generating electrical power. The compressed gas may be delivered to the unit by several means including manual pumps, thermal, chemical, or ammunition based sources, or connection to pressurized canisters. Optional power converting and feedback circuits and pneumatic valves serve to convert the raw output power into useful AC and DC output voltages, and to match the rate of power delivery to the applied electrical load.
U.S. Pat. No. 7,239,066, issued Jul. 3, 2007, to Ott, et al., discloses a piezoelectric power generator that comprises a plurality of piezoelectric devices, an actuator positioned to impart an excitation to the plurality of piezoelectric devices in a predefined sequence, and an electrical conduction system connected to the plurality of piezoelectric devices for conducting an electrical charge created by the excitation. Preferably, the plurality of piezoelectric devices are arranged in a predetermined relationship relative to the actuator whereby only one of the plurality of piezoelectric devices is actuated at a time. For example, the plurality of piezoelectric devices can be arranged in an angular pattern (such as a circular pattern) relative to the actuator. Preferably, a rotational speed of the actuator (24) permits an excitation response for a given piezoelectric device to essentially fully decay before the given piezoelectric device is again excited.
U.S. Pat. No. 7,260,984, issued Aug. 28, 2007, to Roundy, et al., discloses a method of powering one or more electronic devices in a tire monitoring system using a tire pressure based energy scavenger. With this method, a tire is rotated on a surface to generate pressure changes within the tire. These pressure changes are then converted into electrical energy with a transducer and the energy is stored. The electrical energy or stored electrical energy can then be used to power one or more electronic devices in a tire monitoring system, such as a tire pressure sensor, temperature sensor, acceleration profile sensor, and/or a tire wear monitor. A tire monitoring system with a tire pressure based energy scavenger is also provided.
International Application No. PCT/US05/35683, published Apr. 13, 2006, to Raisanen, discloses methods for analyzing characteristics of fluids in the context of an acoustic ejection system. Such a system has a controller, an acoustic radiation generator, and a coupling medium coupling the radiation to a reservoir holding fluid. The methods can use acoustic radiation to both perturb a surface of the fluid in the reservoir and analyze the effect of the perturbation. The methods may use information about prior fluids. The methods of the invention can determine physical characteristics such as speed of sound and viscosity. The methods also include ways to determine a level of acoustic energy suitable to eject a droplet.
The above cited prior art does not disclose a module system that is optimized to generate electrical energy from mechanical and environmental sources, specifically compressive forces, where an array of cymbal transducers is positioned between two rigid plates that are electrically conductive and are coupled to any of the cymbal transducers that are adjacent thereto. Signal conditioning electronics can be coupled to the electrically conductive portions of the plates, and a battery can be connected to the signal conditioning electronics.
As discussed above, solutions to the above described and/or related problems have been long sought without success. Consequently, those skilled in the art will appreciate the present invention that addresses the above and other problems.